4 An Introduction to SCADA Fundamentals and Implementation

An Introduction to SCADA
Fundamentals and
Implementation
Supervisory Control And Data
Acquisition

Electric power generation,
transmission and distribution:
Electric utilities detect current flow and
line voltage, to monitor the operation of
circuit breakers, and to take sections of
the power grid online or offline.
Buildings, facilities and
environments: Facility
managers use SCADA to
control HVAC, refrigeration
units, lighting and entry
systems.
Traffic signals: regulates
traffic lights, controls traffic
flow and detects out-of-
order signals.
Manufacturing: manage parts
inventories for just-in-time
manufacturing, regulate
industrial automation and
robots, and monitor process
and quality control.
Water and sewage: State and
municipal water utilities use
SCADA to monitor and regulate
water flow, reservoir levels, pipe
pressure and other factors.
Mass transit: regulate electricity to
subways, trams and trolley buses; to
automate traffic signals for rail
systems; to track and locate trains
and buses; and to control railroad
crossing gates.
SCADA control

TRANSPORT SYSTEM
Remote Telemetry Unit
(RTU)
Remote Telemetry Unit
(RTU)
SCADA MASTER UNITS
HUMAN COMPUTER
INTERFACE
POWER
DISTRIBUTIO
N
SYSTEM
WATER
DISTRIBUTIO
N
SYSTEM
PROCESS
PLANT
PETROCHEMICAL
PLANT

Dial-up remote
Access
Sites
1-8
16 Digital i/o
2 Analogue inputs
2 control outputs
1 RS232 port
Alarms from remote
equipment
SNMP
monitoring
SITE monitoring
Rs232
10 RouteT LAN
Time Sync Pager
Notification
Remote
Telemetry
Units
(RTU)
DPS TELECOM SCADA
SYSTEMS

A SCADA system performs four functions:
1. Data acquisition
2. Networked data communication
3. Data presentation
4. Control
These functions are performed by four kinds of SCADA components:
1. Sensors (either digital or analogue) and control relays that directly
interface with the managed system.
2. Remote telemetry units (RTUs). These are small computerized
units deployed in the field at specific sites and locations. RTUs
serve as local collection points for gathering reports from sensors
and delivering commands to control relays.
3. SCADA master units. These are larger computer consoles that
serve as the central processor for the SCADA system. Master
units provide a human interface to the system and automatically
regulate the managed system in response to sensor inputs.
4. The communications network that connects the SCADA master
unit to the RTUs in the field.